Exemplary embodiments of the present invention relate to a technology for fabricating a semiconductor device, and more particularly, to a semiconductor device employing a nitride floating capacitor (NFC).
As the size of a semiconductor memory device is required to shrink, cell size also shrinks and the area occupied by a capacitor is decreased as well. However, since capacitors having high capacitance are required to drive a semiconductor device, researchers are developing technology for securing capacitors having high capacitance.
In order to fabricate capacitors having high capacitance, the surface area of a storage node may be expanded or a dielectric layer having a high dielectric constant may be used. When a dielectric layer having a high dielectric constant is used, the stability of conventional processes and reliability work as limitations in the application to a semiconductor device fabrication process. Since the problems hold back the application to the semiconductor device fabrication process, the method of expanding the surface area of a storage node may be desirable. Capacitors for expanding the surface of a storage node include a stack-type capacitor, a concave-type capacitor, a pin-type capacitor, a cylinder-type capacitor and so forth.
Recently, a capacitor has been proposed having a structure where a supporter is applied to a cylinder-type capacitor to maximize the surface area of a storage node. The supporter is a stable structure that can prevent a storage node from leaning down due to the surface tension generated during a dip-out process.
FIGS. 1A and 1B show a conventional capacitor using a supporter. FIG. 1A is a plan view of the conventional capacitor, and FIG. 1B is a photograph showing a sectional view of a capacitor having a structure using a supporter cut along a line X-X′ in FIG. 1A.
Referring to FIGS. 1A and 1B, the cylinder-type storage nodes 11 are formed in plural, and a supporter 12 is formed in the upper portion of the storage nodes. Herein, a structure using a nitride layer as the supporter 12 is referred to as a nitride floating capacitor (NFC).
The conventional capacitor where the storage node 11 is fixed by the supporter 12 has a stable structure that can increase the capacitance of a capacitor by increasing the vertical height of the capacitor and expanding the surface area of the storage node 11, and prevent the storage node 11 from leaning down due to the surface tension generated during a subsequent dip-out process.
However, since the supporter 12 is formed to support the storage node 11 of one cell region in a conventional semiconductor device, there is a concern in that the leaning phenomenon occurs after the dip-out process performed of each cell region.